Is there a non-surgical treatment for hydrocephalus?

Not really. Although there are medications that decrease spinal fluid production, they do not do enough to treat true hydrocephalus. There are many surgical options, such as a shunt or a third ventriculostomy, but surgery is required for active hydrocephalus.
Not usually. Hydrocephalus is caused by blockage of the "pipes" that drain fluid pockets in/around the brain. Some cause of blockage due to temporary swelling, infection, or tumor responsive to non surgical treatments can improve without surgery. But most causes of hydrocephalus will require surgery.